Note the stigmas flat on the surface of the columns. All Calopogon species have this feature except C. tuberosus, which has the stigma somewhat tucked under the anther or otherwise approximately perpendicular to the column surface

Stigmas pictured for--
multiflorus: https://www.inaturalist.org/observations/30639723
oklahomensis: https://www.inaturalist.org/observations/30639873
pallidus: https://www.inaturalist.org/observations/30640036
tuberosus var. tuberosus: https://www.inaturalist.org/observations/30640304.